theorem zpnpcan2 (a b c: nat): $ a +Z b -Z (a +Z c) = b -Z c $;
| Step | Hyp | Ref | Expression |
|---|
| 1 |
|
eqtr3 |
a +Z b -Z a -Z c = a +Z b -Z (a +Z c) -> a +Z b -Z a -Z c = b -Z c -> a +Z b -Z (a +Z c) = b -Z c |
| 2 |
|
zsubsub |
a +Z b -Z a -Z c = a +Z b -Z (a +Z c) |
| 3 |
1, 2 |
ax_mp |
a +Z b -Z a -Z c = b -Z c -> a +Z b -Z (a +Z c) = b -Z c |
| 4 |
|
zsubeq1 |
a +Z b -Z a = b -> a +Z b -Z a -Z c = b -Z c |
| 5 |
|
zpncan2 |
a +Z b -Z a = b |
| 6 |
4, 5 |
ax_mp |
a +Z b -Z a -Z c = b -Z c |
| 7 |
3, 6 |
ax_mp |
a +Z b -Z (a +Z c) = b -Z c |
Axiom use
axs_prop_calc
(ax_1,
ax_2,
ax_3,
ax_mp,
itru),
axs_pred_calc
(ax_gen,
ax_4,
ax_5,
ax_6,
ax_7,
ax_10,
ax_11,
ax_12),
axs_set
(elab,
ax_8),
axs_the
(theid,
the0),
axs_peano
(peano1,
peano2,
peano5,
addeq,
muleq,
add0,
addS,
mul0,
mulS)